Test Methods For Formability Of Sheet Metal

Sheet metal forming simulation is almost meaningless without accurate material data.

Test methods for formability of sheet metal.

In this chapter 1 sheet metal formability tests such as the tensile test the plane strain test and the in plane stretching test are analyzed. The fem and experimental methods were used in order to demonstrate how two dimensional in plane simulation can help interpret and develop such tests as well as to understand the nature of material behavior and governing mechanics. Astm e646 stan dard test method for tensile strain hardening exponents of metallic sheet materials governs the determination of the strain hardening exponent. It is assumed or considered that the larger is the value of total elongation the more formable is the material.

During rolling the sheet develops anisotropy both in the plane of the sheet called planer anisotropy as well in the thickness of sheet called anisotropy ratio. Astm e646 is a tensile test that measures the stress strain response in the plastic region prior to necking dp 0. Astm e517 standard test method for plastic strain ratio r for sheet metal decides its determination. Tips for sheet metal testing.

The r value of sheet varies with the applied axial strain and as such should be reported at the tested strain level unlike many other materials with r values that stay constant over the range of plastic strains. Anisotropy in sheet metals. The old saying garbage in garbage out rings true in this regard. In sheet metal industry the initial estimation of formability is usually based on total elongation measured from the tensile test.